Narrowband definition for enhanced machine type communication

ABSTRACT

Aspects of the present disclosure provide a method performed by a wireless device. The method generally includes identifying one or more narrowband regions within a wider system bandwidth, based on an amount of available resources in the system bandwidth, and communicating using at least one of the identified narrowband regions.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/067,029, filed on Mar. 10, 2016, entitled “NARROWBAND DEFINITION FORENCHANCED MACHINE TYPE COMMUNICATION”, which claims priority to U.S.Provisional Patent Application No. 62/162,623, filed on May 15, 2015,which are hereby expressly incorporated by reference in their entirety.

BACKGROUND I. Field of the Invention

Certain aspects of the present disclosure generally relate to wirelesscommunications and, more particularly, to narrowband definitions forenhanced machine type communication(s) (eMTC).

II. Background

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, data, and so on. Thesesystems may be multiple-access systems capable of supportingcommunication with multiple users by sharing the available systemresources (e.g., bandwidth and transmit power). Examples of suchmultiple-access systems include code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, 3rd Generation PartnershipProject (3GPP) Long Term Evolution (LTE)/LTE-Advanced systems andorthogonal frequency division multiple access (OFDMA) systems.

Generally, a wireless multiple-access communication system cansimultaneously support communication for multiple wireless terminals.Each terminal communicates with one or more base stations viatransmissions on the forward and reverse links. The forward link (ordownlink) refers to the communication link from the base stations to theterminals, and the reverse link (or uplink) refers to the communicationlink from the terminals to the base stations. This communication linkmay be established via a single-input single-output, multiple-inputsingle-output or a multiple-input multiple-output (MIMO) system.

A wireless communication network may include a number of base stationsthat can support communication for a number of wireless devices.Wireless devices may include user equipments (UEs). Some UEs may beconsidered enhanced or evolved machine-type communication (eMTC) UEsthat may communicate with a base station, another device (e.g., remotedevice), or some other entity. MTC may refer to communication involvingat least one remote device on at least one end of the communication andmay include forms of data communication which involve one or moreentities that do not necessarily need human interaction. MTC UEs mayinclude UEs that are capable of MTC communications with MTC serversand/or other MTC devices through Public Land Mobile Networks (PLMN), forexample.

SUMMARY

Certain aspects of the present disclosure provide a method, performed bya wireless device. The method generally includes identifying one or morenarrowband regions within a wider system bandwidth, based on an amountof available resources in the system bandwidth, and communicating usingat least one of the identified narrowband regions.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus generally includes at least oneprocessor configured to identify one or more narrowband regions within awider system bandwidth, based on an amount of available resources in thesystem bandwidth, and communicate using at least one of the identifiednarrowband regions, and a memory coupled to the at least one processor.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus generally includes means foridentifying one or more narrowband regions within a wider systembandwidth, based on an amount of available resources in the systembandwidth, and means for communicating using at least one of theidentified narrowband regions.

Certain aspects of the present disclosure provide a computer-readablemedium for wireless communications. The computer-readable mediumgenerally includes code to identify one or more narrowband regionswithin a wider system bandwidth, based on an amount of availableresources in the system bandwidth, and code to communicate using atleast one of the identified narrowband regions.

Numerous other aspects are provided including methods, apparatus,systems, computer program products, and processing systems. To theaccomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram conceptually illustrating an example of awireless communication network, in accordance with certain aspects ofthe present disclosure.

FIG. 2 shows a block diagram conceptually illustrating an example of abase station in communication with a user equipment (UE) in a wirelesscommunications network, in accordance with certain aspects of thepresent disclosure.

FIG. 3 is a block diagram conceptually illustrating an example of aframe structure in a wireless communications network, in accordance withcertain aspects of the present disclosure.

FIG. 4 is a block diagram conceptually illustrating two exemplarysubframe formats with the normal cyclic prefix.

FIG. 5 illustrates an exemplary subframe configuration for eMTC, inaccordance with certain aspects of the present disclosure.

FIG. 6 is a flow diagram illustrating example operations for wirelesscommunications by a wireless device, in accordance with certain aspectsof the present disclosure.

FIG. 7 illustrates an exemplary resource block configuration for eMTCoperations, in accordance with certain aspects of the presentdisclosure.

FIGS. 8A-8C illustrate example narrowband region definitions, inaccordance with certain aspects of the present disclosure.

FIGS. 9A-9C illustrate example narrowband region definitions, inaccordance with certain aspects of the present disclosure.

DETAILED DESCRIPTION

Aspects of the present disclosure provide techniques that may be used todefine narrowband regions for enhanced machine type communication(eMTC), performed by a wireless device.

The techniques described herein may be used for various wirelesscommunication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asuniversal terrestrial radio access (UTRA), cdma2000, etc. UTRA includeswideband CDMA (WCDMA), time division synchronous CDMA (TD-SCDMA), andother variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856standards. A TDMA network may implement a radio technology such asglobal system for mobile communications (GSM). An OFDMA network mayimplement a radio technology such as evolved UTRA (E-UTRA), ultra mobilebroadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20,Flash-OFDM®, etc. UTRA and E-UTRA are part of universal mobiletelecommunication system (UMTS). 3GPP Long Term Evolution (LTE) andLTE-Advanced (LTE-A), in both frequency division duplex (FDD) and timedivision duplex (TDD), are new releases of UMTS that use E-UTRA, whichemploys OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA,UMTS, LTE, LTE-A and GSM are described in documents from an organizationnamed “3rd Generation Partnership Project” (3GPP). cdma2000 and UMB aredescribed in documents from an organization named “3rd GenerationPartnership Project 2” (3GPP2). The techniques described herein may beused for the wireless networks and radio technologies mentioned above aswell as other wireless networks and radio technologies. For clarity,certain aspects of the techniques are described below forLTE/LTE-Advanced, and LTE/LTE-Advanced terminology is used in much ofthe description below. LTE and LTE-A are referred to generally as LTE.

FIG. 1 illustrates an example wireless communication network 100, inwhich aspects of the present disclosure may be practiced. For example,techniques presented herein may be used to help define narrowbandregions for enhanced machine type communication (eMTC), performed by awireless device.

The network 100 may be an LTE network or some other wireless network.Wireless network 100 may include a number of evolved Node Bs (eNBs) 110and other network entities. An eNB is an entity that communicates withuser equipments (UEs) and may also be referred to as a base station, aNode B, an access point, etc. Each eNB may provide communicationcoverage for a particular geographic area. In 3GPP, the term “cell” canrefer to a coverage area of an eNB and/or an eNB subsystem serving thiscoverage area, depending on the context in which the term is used.

An eNB may provide communication coverage for a macro cell, a pico cell,a femto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a closed subscriber group (CSG)). An eNB for a macro cell may bereferred to as a macro eNB. An eNB for a pico cell may be referred to asa pico eNB. An eNB for a femto cell may be referred to as a femto eNB ora home eNB (HeNB). In the example shown in FIG. 1, an eNB 110 a may be amacro eNB for a macro cell 102 a, an eNB 110 b may be a pico eNB for apico cell 102 b, and an eNB 110 c may be a femto eNB for a femto cell102 c. An eNB may support one or multiple (e.g., three) cells. The terms“eNB”, “base station” and “cell” may be used interchangeably herein.

Wireless network 100 may also include relay stations. A relay station isan entity that can receive a transmission of data from an upstreamstation (e.g., an eNB or a UE) and send a transmission of the data to adownstream station (e.g., a UE or an eNB). A relay station may also be aUE that can relay transmissions for other UEs. In the example shown inFIG. 1, a relay station 110 d may communicate with macro eNB 110 a and aUE 120 d in order to facilitate communication between eNB 110 a and UE120 d. A relay station may also be referred to as a relay eNB, a relaybase station, a relay, etc.

Wireless network 100 may be a heterogeneous network that includes eNBsof different types, e.g., macro eNBs, pico eNBs, femto eNBs, relay eNBs,etc. These different types of eNBs may have different transmit powerlevels, different coverage areas, and different impact on interferencein wireless network 100. For example, macro eNBs may have a hightransmit power level (e.g., 5 to 40 Watts) whereas pico eNBs, femtoeNBs, and relay eNBs may have lower transmit power levels (e.g., 0.1 to2 Watts).

A network controller 130 may couple to a set of eNBs and may providecoordination and control for these eNBs. Network controller 130 maycommunicate with the eNBs via a backhaul. The eNBs may also communicatewith one another, e.g., directly or indirectly via a wireless orwireline backhaul.

UEs 120 (e.g., 120 a, 120 b, 120 c) may be dispersed throughout wirelessnetwork 100, and each UE may be stationary or mobile. A UE may also bereferred to as an access terminal, a terminal, a mobile station, asubscriber unit, a station, etc. Some examples of UEs may includecellular phones, smart phones, personal digital assistants (PDAs),wireless modems, handheld devices, tablets, laptop computers, netbooks,smartbooks, ultrabooks, entertainment devices (e.g., gaming devices,music players), navigation devices, cameras, wearable devices (e.g.,smart watches, smart clothing, smart glasses, smart goggles, heads-updisplay devices, smart wrist bands, smart jewelry (e.g., smart ring,smart bracelet)), medical devices, healthcare devices, vehiculardevices, etc. MTC UEs may include sensors, meters, monitors, securitydevices, location tags, robots/robotic devices, drones, etc. Some MTCUEs, and other UEs, may be implemented as internet of things (IoT)(e.g., narrowband IoT (NB-IoT)) or internet of everything (IoE) devices.In FIG. 1, a solid line with double arrows indicates desiredtransmissions between a UE and a serving eNB, which is an eNB designatedto serve the UE on the downlink and/or uplink. A dashed line with doublearrows indicates potentially interfering transmissions between a UE andan eNB.

FIG. 2 shows a block diagram of a design of base station/eNB 110 and UE120, which may be one of the base stations/eNBs and one of the UEs inFIG. 1. Base station 110 may be equipped with T antennas 234 a through234 t, and UE 120 may be equipped with R antennas 252 a through 252 r,where in general T≥1 and R≥1.

At base station 110, a transmit processor 220 may receive data from adata source 212 for one or more UEs, select one or more modulation andcoding schemes (MCS) for each UE based on CQIs received from the UE,process (e.g., encode and modulate) the data for each UE based on theMCS(s) selected for the UE, and provide data symbols for all UEs.Transmit processor 220 may also process system information (e.g., forSRPI, etc.) and control information (e.g., CQI requests, grants, upperlayer signaling, etc.) and provide overhead symbols and control symbols.Processor 220 may also generate reference symbols for reference signals(e.g., the CRS) and synchronization signals (e.g., the PSS and SSS). Atransmit (TX) multiple-input multiple-output (MIMO) processor 230 mayperform spatial processing (e.g., precoding) on the data symbols, thecontrol symbols, the overhead symbols, and/or the reference symbols, ifapplicable, and may provide T output symbol streams to T modulators(MODs) 232 a through 232 t. Each modulator 232 may process a respectiveoutput symbol stream (e.g., for OFDM, etc.) to obtain an output samplestream. Each modulator 232 may further process (e.g., convert to analog,amplify, filter, and upconvert) the output sample stream to obtain adownlink signal. T downlink signals from modulators 232 a through 232 tmay be transmitted via T antennas 234 a through 234 t, respectively.

At UE 120, antennas 252 a through 252 r may receive the downlink signalsfrom base station 110 and/or other base stations and may providereceived signals to demodulators (DEMODs) 254 a through 254 r,respectively. Each demodulator 254 may condition (e.g., filter, amplify,downconvert, and digitize) its received signal to obtain input samples.Each demodulator 254 may further process the input samples (e.g., forOFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtainreceived symbols from all R demodulators 254 a through 254 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 258 may process (e.g., demodulateand decode) the detected symbols, provide decoded data for UE 120 to adata sink 260, and provide decoded control information and systeminformation to a controller/processor 280. A channel processor maydetermine RSRP, RSSI, RSRQ, CQI, etc.

On the uplink, at UE 120, a transmit processor 264 may receive andprocess data from a data source 262 and control information (e.g., forreports comprising RSRP, RSSI, RSRQ, CQI, etc.) fromcontroller/processor 280. Processor 264 may also generate referencesymbols for one or more reference signals. The symbols from transmitprocessor 264 may be precoded by a TX MIMO processor 266 if applicable,further processed by modulators 254 a through 254 r (e.g., for SC-FDM,OFDM, etc.), and transmitted to base station 110. At base station 110,the uplink signals from UE 120 and other UEs may be received by antennas234, processed by demodulators 232, detected by a MIMO detector 236 ifapplicable, and further processed by a receive processor 238 to obtaindecoded data and control information sent by UE 120. Processor 238 mayprovide the decoded data to a data sink 239 and the decoded controlinformation to controller/processor 240. Base station 110 may includecommunication unit 244 and communicate to network controller 130 viacommunication unit 244. Network controller 130 may include communicationunit 294, controller/processor 290, and memory 292.

Controllers/processors 240 and 280 may direct the operation at basestation 110 and UE 120, respectively, to perform techniques presentedherein for defining narrowband regions for enhanced machine typecommunication (eMTC) to use for communications between a UE (e.g., aneMTC UE) and a base station (e.g., an eNodeB). For example,controller/processor 240 and/or other controllers, processors andmodules at base station 110, and controller/processor 280 and/or othercontrollers, processors and modules at UE 120, may perform or directoperations of base station 110 and UE 120, respectively. For example,controller/processor 240 and/or other controllers, processors andmodules at base station 110, may perform or direct operations 600 shownin FIG. 6. For example, controller/processor 280 and/or othercontrollers, processors and modules at UE 120, may perform or directoperations 600 shown in FIG. 6. Memories 242 and 282 may store data andprogram codes for base station 110 and UE 120, respectively. A scheduler246 may schedule UEs for data transmission on the downlink and/oruplink.

FIG. 3 shows an exemplary frame structure 300 for FDD in LTE. Thetransmission timeline for each of the downlink and uplink may bepartitioned into units of radio frames. Each radio frame may have apredetermined duration (e.g., 10 milliseconds (ms)) and may bepartitioned into 10 subframes with indices of 0 through 9. Each subframemay include two slots. Each radio frame may thus include 20 slots withindices of 0 through 19. Each slot may include L symbol periods, e.g.,seven symbol periods for a normal cyclic prefix (as shown in FIG. 3) orsix symbol periods for an extended cyclic prefix. The 2L symbol periodsin each subframe may be assigned indices of 0 through 2L-1.

In LTE, an eNB may transmit a primary synchronization signal (PSS) and asecondary synchronization signal (SSS) on the downlink in the center ofthe system bandwidth for each cell supported by the eNB. The PSS and SSSmay be transmitted in symbol periods 6 and 5, respectively, in subframes0 and 5 of each radio frame with the normal cyclic prefix, as shown inFIG. 3. The PSS and SSS may be used by UEs for cell search andacquisition. The eNB may transmit a cell-specific reference signal (CRS)across the system bandwidth for each cell supported by the eNB. The CRSmay be transmitted in certain symbol periods of each subframe and may beused by the UEs to perform channel estimation, channel qualitymeasurement, and/or other functions. The eNB may also transmit aphysical broadcast channel (PBCH) in symbol periods 0 to 3 in slot 1 ofcertain radio frames. The PBCH may carry some system information. TheeNB may transmit other system information such as system informationblocks (SIBs) on a physical downlink shared channel (PDSCH) in certainsubframes. The eNB may transmit control information/data on a physicaldownlink control channel (PDCCH) in the first B symbol periods of asubframe, where B may be configurable for each subframe. The eNB maytransmit traffic data and/or other data on the PDSCH in the remainingsymbol periods of each subframe.

FIG. 4 shows two exemplary subframe formats 410 and 420 with the normalcyclic prefix. The available time frequency resources may be partitionedinto resource blocks. Each resource block may cover 12 subcarriers inone slot and may include a number of resource elements. Each resourceelement may cover one subcarrier in one symbol period and may be used tosend one modulation symbol, which may be a real or complex value.

Subframe format 410 may be used for two antennas. A CRS may betransmitted from antennas 0 and 1 in symbol periods 0, 4, 7 and 11. Areference signal is a signal that is known a priori by a transmitter anda receiver and may also be referred to as pilot. A CRS is a referencesignal that is specific for a cell, e.g., generated based on a cellidentity (ID). In FIG. 4, for a given resource element with label Ra, amodulation symbol may be transmitted on that resource element fromantenna a, and no modulation symbols may be transmitted on that resourceelement from other antennas. Subframe format 420 may be used with fourantennas. A CRS may be transmitted from antennas 0 and 1 in symbolperiods 0, 4, 7 and 11 and from antennas 2 and 3 in symbol periods 1 and8. For both subframe formats 410 and 420, a CRS may be transmitted onevenly spaced subcarriers, which may be determined based on cell ID.CRSs may be transmitted on the same or different subcarriers, dependingon their cell IDs. For both subframe formats 410 and 420, resourceelements not used for the CRS may be used to transmit data (e.g.,traffic data, control data, and/or other data).

The PSS, SSS, CRS and PBCH in LTE are described in 3GPP TS 36.211,entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); PhysicalChannels and Modulation,” which is publicly available.

An interlace structure may be used for each of the downlink and uplinkfor FDD in LTE. For example, Q interlaces with indices of 0 through Q−1may be defined, where Q may be equal to 4, 6, 8, 10, or some othervalue. Each interlace may include subframes that are spaced apart by Qframes. In particular, interlace q may include subframes q, q+Q , q+2Q,etc., where q ∈ {0, . . . , Q−1}.

The wireless network may support hybrid automatic retransmission request(HARQ) for data transmission on the downlink and uplink. For HARQ, atransmitter (e.g., an eNB) may send one or more transmissions of apacket until the packet is decoded correctly by a receiver (e.g., a UE)or some other termination condition is encountered. For synchronousHARQ, all transmissions of the packet may be sent in subframes of asingle interlace. For asynchronous HARQ, each transmission of the packetmay be sent in any subframe.

A UE may be located within the coverage of multiple eNBs. One of theseeNBs may be selected to serve the UE. The serving eNB may be selectedbased on various criteria such as received signal strength, receivedsignal quality, pathloss, etc. Received signal quality may be quantifiedby a signal-to-noise-and-interference ratio (SINR), or a referencesignal received quality (RSRQ), or some other metric. The UE may operatein a dominant interference scenario in which the UE may observe highinterference from one or more interfering eNBs.

Narrowband EMTC

As noted above, techniques presented herein may be used to help UEs(e.g., eMTC UEs) determine narrowbands and hopping pattern for use witheMTC.

The focus of traditional LTE design (e.g., for legacy “non MTC” devices)is on the improvement of spectral efficiency, ubiquitous coverage, andenhanced quality of service (QoS) support. Current LTE system downlink(DL) and uplink (UL) link budgets are designed for coverage of high enddevices, such as state-of-the-art smartphones and tablets, which maysupport a relatively large DL and UL link budget.

However, low cost, low rate devices need to be supported as well. Forexample, certain standards (e.g., LTE Release 12) have introduced a newtype of UE (referred to as a category 0 UE) generally targeting low costdesigns or machine type communications. For machine type communications(MTC), various requirements may be relaxed as only a limited amount ofinformation may need to be exchanged. For example, relative to legacyUEs, maximum bandwidth may be reduced, a single receive radio frequency(RF) chain may be used, peak rate may be reduced (e.g., a maximum of 100bits for a transport block size), transmit power may be reduced, Rank 1transmission may be used, and half duplex operation may be performed.

In some cases, if half-duplex operation is performed, MTC UEs may have arelaxed switching time to transition from transmitting to receiving (orreceiving to transmitting). For example, the switching time may berelaxed from 20 μs for regular UEs to 1 ms for MTC UEs. Release 12 MTCUEs may still monitor downlink (DL) control channels in the same way asregular UEs, for example, monitoring for wideband control channels inthe first few symbols (e.g., PDCCH) as well as narrowband controlchannels occupying a relatively narrowband, but spanning a length of asubframe (e.g., ePDCCH).

Certain standards (e.g., LTE Release 13) may introduce support forvarious additional MTC enhancements, referred to herein as enhanced MTC(or eMTC). For example, eMTC may provide MTC UEs with coverageenhancements up to 15 dB.

As illustrated in the subframe structure 500 of FIG. 5, eMTC UEs cansupport narrowband operation while operating in a wider system bandwidth(e.g., 1.4/3/5/10/15/20 MHz). In the example illustrated in FIG. 5, aconventional legacy control region 510 may span system bandwidth of afirst few symbols, while a narrowband region 530 occupies a portion of alarger region 520 of the system bandwidth. In some cases, an MTC UEmonitoring the narrowband region may operate at 1.4 MHz or 6 resourceblocks (RBs).

As noted above, eMTC UEs may be able to operate in a cell with abandwidth larger than 6 RBs. Within this larger bandwidth, each eMTC UEmay still operate (e.g., monitor/receive/transmit) while abiding by a6-physical resource block (PRB) constraint. In some cases, differenteMTC UEs may be served by different narrowband regions (e.g., with eachspanning 6-PRB blocks) within the system bandwidth. As the systembandwidth may span from 1.4 to 20 MHz, or from 6 to 100 RBs, multiplenarrowband regions may exist within the larger bandwidth. An eMTC UE mayalso switch or hop between multiple narrowband regions in order toreduce interference.

While the size of DL and UL narrowband regions are defined, the locationof the available narrowbands and hopping pattern for eMTC UEs within thelarger bandwidth is not fixed and may need definition.

As bandwidth is a limited resource, narrowband regions should be definedsuch that all or almost all RBs are grouped into a narrowband regionwith as few empty RBs as possible. In certain systems, the number ofPRBs within a given bandwidth is not a multiple of six. A narrowbandregion of 6 RBs operates at 1.4 MHz, while system bandwidths may be 1.4,3, 5, 10, 15, and 20 MHz, corresponding to 6, 15, 25, 50, 75, and 100RBs, only one of which is a multiple of 6. For example, a 5 MHzbandwidth cell has 15 PRBs available, which equals 2.5 narrowbandregions. Thus, for many LTE bandwidths, the system bandwidth cannot beevenly split into narrowband regions. It may be advantageous to definenarrowband regions such as to minimize the number of RBs that are notgrouped into narrowband regions.

Narrowband Definitions for EMTC

FIG. 6 is a flow diagram illustrating example operations 600 forwireless communications by a wireless device, in accordance with certainaspects of the present disclosure. The wireless device may be, forexample, an eNB to communicate with UEs over narrowband regions, or a UEto communicate with eNBs over narrowband regions. The operations maybegin, at 602, by identifying one or more narrowband regions within awider system bandwidth, based on an amount of available resources in thesystem bandwidth. At 604, the operations include communicating using atleast one of the identified narrowband regions.

FIG. 7 illustrates an exemplary resource block configuration 700 foreMTC operations, in accordance with certain aspects of the presentdisclosure. In certain systems, the center 6 RBs may be used for PSS/SSSand/or paging. For bandwidths with an odd number of RBs (e.g., 1.4 MHz,3 MHz, 5 MHz, etc.), the central 6 RBs may not be aligned with physicalresource blocks. For example, as shown in FIG. 6, the center 6 RBs 702for a 3 MHz bandwidth are resource blocks 5-9 and half of resource block4 and half of resource block 10. Where a narrowband region is defined inthe center 6 RB, an eMTC tuned to the narrowband region forsynchronization purposes would not need to retune to receive pagingtransmissions, potentially resulting in energy savings.

FIG. 8A illustrates an example narrowband region definition 800A, inaccordance with certain aspects of the present disclosure. According tocertain aspects, a narrowband region, 802A, may be defined based on thecenter 6 RB. Where the number of available RBs is not even and center 6RBs are not aligned with the wideband RB boundaries, narrowband region802A may also not be aligned with the wideband RB boundaries. Forexample, narrowband (NB) region 802A may be defined as extending from RB4.5 to RB 10.5. Alternatively, the center 6 RB region may be rounded upone RB to 7 Bs. Wideband and eMTC devices may continue to monitor onlythe center 6 RBs for paging, but also by extending the region 0.5 RBabove and below the center 6 RB, for example, extending from RB 4 to RB11. This allows NB region 802A to be aligned with the wideband RBboundaries. Groups of 6 RBs from the wideband edges may then be definedas narrowband regions, in this case, NB region 804A and NB region 806A,until the entire wideband bandwidth is divided into narrowband regions.Where the total wideband bandwidth is not divisible evenly into 6 RBregions, overlap between the narrowband regions will occur. Here, forexample, NB region 804A and NB region 806A would both overlap with NBregion 802A. This results in a total number of narrowband regions equalto the ceiling of the number of resource blocks divided by 6, orceil(nRB/6).

In certain cases, it may be desirable to have non-overlapping narrowbandregions. As noted above, where the total number of RBs is not a multipleof six, it is not possible to divide the total number of RBs into fixedsized narrowband regions such that each wideband RB is used. However,using smaller sized narrowband regions in conjunction with the 6 RBnarrowband region would allow for each wideband RB to be used. Forexample, where the center 6 RBs have been rounded up to 7 to align withthe wideband RB boundaries, narrowband regions may be selected in groupsof 6 RBs inward from each edge.

FIGS. 8B illustrate example narrowband region definition 800B, inaccordance with certain aspects of the present disclosure. Asillustrated in FIG. 8B, the narrowband regions directly adjacent to NBregion 802B, rather than overlapping the NB region 802B, are reduced insize. As illustrated here, NB region 804B and NB region 806B are 4 RBsrather than 6 RBs. Such an arrangement would place the smallernarrowband regions next to the NB region 802B. Alternatively, NB regionsmay be selected in groups of 6 RBs outward from the NB region 802B. Suchan arrangement would place the smaller narrowband regions next to theedges of the wideband bandwidth. As seen in FIG. 8C, in examplenarrowband region definition 800C where the center 6 RBs have not beenrounded up, half an RB to either side of the NB region 802C may be leftunassigned 804C to narrowband regions. This applies, e.g., only towideband bandwidths with an odd number of RBs.

In certain systems, the narrowband mapping may be different for uplinkand downlink. For example, on the downlink, some systems use the center6 RB for PSS/SSS/PBCH and/or paging. However, no such requirements mayexist on the uplink. For simplicity, downlink narrowband regions may bealigned based on the center 6 RBs. Alternatively, uplink narrowbandregions may also be defined such that there are smaller narrowbandregions along the edges of the wideband bandwidth reserved for PUCCH.

FIGS. 9A-9C illustrate example narrowband region definitions 900A-900C,respectively, in accordance with certain aspects of the presentdisclosure. In certain cases, the smaller narrowband regions may bedefined such that the total number of resource blocks divided by 6(e.g., mod(nRB, 6)) are allocated at the bandwidth edges for the smallernarrowband regions. These RBs may be allocated equally between the edgessuch that the individual sizes of the smaller RBs equals, e.g.,(mod(nRB, 6))/2. Narrowband regions of 6 RBs may then be allocatedbetween the edges. For example, for a 3 MHz, 15 RB wideband bandwidth inFIG. 9A, mod(15, 6) yields 3 RBs, which are split into two 1.5 RBnarrowband regions NB region 902A and NB region 904A along the edge ofthe wideband bandwidth. The remaining RBs between the edges may then beequally allocated into 6 RB narrowband regions, as shown in NB region906A and NB region 908A. However, equally dividing RBs along the edgesinto narrowband regions may result in fractional RB allocations, as inNB region 902A and NB region 904A, as well as narrowband regions thatmay not be aligned with the wideband RBs, such as NB region 906A and NBregion 908A in RB 7.

Where a center 6 RB alignment is not being maintained, the RBdistribution into narrowband regions may be asymmetrical. Theasymmetrical distribution may allow the narrowband regions to be alignedwith the wideband RBs where there is an odd number of wideband RBs. Forexample, as illustrated in FIG. 8B, where the individual sizes of thesmaller RBs, as determined by (mod(nRB, 6))/2, results in a non-integer,one of the smaller narrowband regions may be rounded down (NB region902B), here to one RB, and the other smaller narrowband region roundedup (NB region 904B), here two RBs. This rounding allows the narrowbandedges to be aligned with the wideband RB edges. Other narrowbandregions, such as NB region 906B and NB region 908B may also be adjustedto be aligned with the wideband RB edges.

Alternatively, rather than rounding the size of one smaller narrowbandregion up and the other down, the size of both smaller narrowbandregions may be rounded down. For example, as illustrated in FIG. 8C,both NB region 902C and NB region 904C are rounded down to 1 RB each.Additional narrowband regions, e.g., NB region 906C and NB region 908C,between the edges may then be defined. A remaining RB in the center RBmay then be defined as an additional smaller narrowband region NB region910C, such that smaller narrowband regions are defined both at the edgeand in the center of the wideband bandwidth.

Narrowband Frequency Hopping for EMTC

LTE includes hopping between frequencies in a particular pattern toimprove transmission diversity. This hopping pattern may be signaled toeMTC devices explicitly in the scheduling grant. For eMTC devices, theflexibility offered by explicit signaling may be outweighed by theadditional power usage to monitor for the signaling. According tocertain aspects, signaling may be simplified by basing the hoppingpattern on the initial narrowband region used for communications. Thishopping may be performed within a pair of narrowband regions, or basedon a fixed pattern.

As an example, for a 10 MHz bandwidth with 9 narrowband regions numberedfrom 0 to 8, four sets of narrowband pairs may be defined. Thesenarrowband pairs may be, for example, {0,5}, {1,6}, {2,7}, and {3,8}.Hopping behavior may be defined such that hopping may be performed fromone member of the narrowband pair to the other member of the narrowbandpair. The specific hopping behavior then is based on the narrowbandregion initially identified for communications. That is, where aparticular wireless device receives an indication that it is to usenarrowband region 0 initially for communications, the wireless devicewould know to next hop to narrowband region 5 for the nextcommunication, without any other additional signaling. This initialindication may be derived from SIB, MIB, or other types of signaling.Additionally, hopping may be performed based off a pattern rather thanreciprocal hopping. In such implementations, an initial hop forward offive narrowband regions from 0 to 5 may be followed by a hop back offour narrowband regions, e.g., from 5 to 1. In either case, the hoppingpattern, e.g., for a given bundle size, is predetermined (e.g., fixed byspecification or SIB1/other signaling) based on the initially identifiednarrowband region and there is no need to signal the specific pattern ina downlink or uplink grant. Additionally, specific patterns and pairsmay be defined for each of the system bandwidths (e.g., 3, 5, 10, 15,and 20 MHz).

In certain systems, frequency hopping patterns may be further definedsuch that, for example, the initially identified narrowband region usedfor downlink is associated with a narrowband region hopping for theuplink, and vice versa. For example, again for a 10 MHz bandwidth, wherea particular wireless device receives an indication that it is to usenarrowband region 0 initially for downlink, the wireless device wouldknow to next hop to an associated uplink narrowband region 5 for sendinga response. Likewise, receiving a DL grant on a particular narrowbandregion may indicate to the wireless device to hop to an associateddownlink narrowband region to receive the downlink transmission.Similarly, an UL grant on a particular narrowband region may indicate tothe wireless device to hop to an associated uplink narrowband region totransmit. Similarly, a random access uplink transmission on a particularnarrowband region may indicate to the wireless device to hop to anassociated downlink narrowband region to receive the random accessresponse.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover: a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

As used herein, the term “identifying” encompasses a wide variety ofactions. For example, “identifying” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “identifying” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“identifying” may include resolving, selecting, choosing, establishingand the like.

In some cases, rather than actually communicating a frame, a device mayhave an interface to communicate a frame for transmission or reception.For example, a processor may output a frame, via a bus interface, to anRF front end for transmission. Similarly, rather than actually receivinga frame, a device may have an interface to obtain a frame received fromanother device. For example, a processor may obtain (or receive) aframe, via a bus interface, from an RF front end for transmission.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Softwareshall be construed broadly to mean instructions, data, code, or anycombination thereof, whether referred to as software, firmware,middleware, code, microcode, hardware description language, machinelanguage, or otherwise. Generally, where there are operationsillustrated in figures, those operations may have correspondingcounterpart means-plus-function components.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in Figures, those operations maybe performed by any suitable corresponding counterpartmeans-plus-function components.

For example, means for identifying and/or means for communicating mayinclude one or more processors or other elements, such as the transmitprocessor 220, the controller/processor 240, the receive processor 238,and/or antenna(s) 234 of the base station 110 illustrated in FIG. 2 orthe transmit processor 264, the controller/processor 280, the receiveprocessor 258, and/or antenna(s) 252 of the user equipment 120illustrated in FIG. 2.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or combinations thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as hardware,software, or combinations thereof. To clearly illustrate thisinterchangeability of hardware and software, various illustrativecomponents, blocks, modules, circuits, and steps have been describedabove generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination thereof. A softwaremodule may reside in RAM memory, flash memory, ROM memory, EPROM memory,EEPROM memory, phase change memory, registers, hard disk, a removabledisk, a CD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, or combinations thereof. Ifimplemented in software, the functions may be stored on or transmittedover as one or more instructions or code on a computer-readable medium.Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage media may be anyavailable media that can be accessed by a general purpose or specialpurpose computer. By way of example, and not limitation, suchcomputer-readable media can comprise RAM, ROM, EEPROM, CD/DVD or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code means in the form of instructions or data structures andthat can be accessed by a general-purpose or special-purpose computer,or a general-purpose or special-purpose processor. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave, then the coaxial cable, fiber optic cable, twisted pair,DSL, or wireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method for wireless communications by awireless device, comprising: identifying one or more narrowband regionswithin a wider system bandwidth, based on an amount of availableresources in the system bandwidth; and communicating using at least oneof the identified narrowband regions.